X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=schedule.cc;h=cca60ebfba45795252c4e3de97d1223b934aa0f4;hp=691c6f43088595300ac198783328d4b102c8b0f4;hb=e919b30ee6f7aa594c61fc305e6e88e789dbd700;hpb=517d8ce6cc880bb523ee55005afdcad1ec551e64

diff --git a/schedule.cc b/schedule.cc
index 691c6f4..cca60eb 100644
--- a/schedule.cc
+++ b/schedule.cc
@@ -1,26 +1,136 @@
+#include <string.h>
+#include <stdlib.h>
+
 #include "threads.h"
 #include "schedule.h"
 #include "common.h"
 #include "model.h"
 
+/** Constructor */
+Scheduler::Scheduler() :
+	enabled(NULL),
+	enabled_len(0),
+	curr_thread_index(0),
+	current(NULL)
+{
+}
+
+void Scheduler::set_enabled(Thread *t, enabled_type_t enabled_status) {
+	int threadid=id_to_int(t->get_id());
+	if (threadid>=enabled_len) {
+		enabled_type_t *new_enabled = (enabled_type_t *)snapshot_malloc(sizeof(enabled_type_t) * (threadid + 1));
+		memset(&new_enabled[enabled_len], 0, (threadid+1-enabled_len)*sizeof(enabled_type_t));
+		if (enabled != NULL) {
+			memcpy(new_enabled, enabled, enabled_len*sizeof(enabled_type_t));
+			snapshot_free(enabled);
+		}
+		enabled=new_enabled;
+		enabled_len=threadid+1;
+	}
+	enabled[threadid]=enabled_status;
+}
+
+/**
+ * @brief Check if a Thread is currently enabled
+ * @param t The Thread to check
+ * @return True if the Thread is currently enabled
+ */
+bool Scheduler::is_enabled(Thread *t) const
+{
+	int id = id_to_int(t->get_id());
+	return (id >= enabled_len) ? false : (enabled[id] == THREAD_ENABLED);
+}
+
+/**
+ * Add a Thread to the scheduler's ready list.
+ * @param t The Thread to add
+ */
 void Scheduler::add_thread(Thread *t)
 {
-	DEBUG("thread %d\n", t->get_id());
-	queue.push(t);
+	DEBUG("thread %d\n", id_to_int(t->get_id()));
+	set_enabled(t, THREAD_ENABLED);
 }
 
-Thread *Scheduler::next_thread(void)
+/**
+ * Remove a given Thread from the scheduler.
+ * @param t The Thread to remove
+ */
+void Scheduler::remove_thread(Thread *t)
 {
-	if (queue.empty())
-		return NULL;
+	if (current == t)
+		current = NULL;
+	set_enabled(t, THREAD_DISABLED);
+}
 
-	current = queue.front();
-	queue.pop();
+/**
+ * Prevent a Thread from being scheduled. The sleeping Thread should be
+ * re-awoken via Scheduler::wake.
+ * @param thread The Thread that should sleep
+ */
+void Scheduler::sleep(Thread *t)
+{
+	set_enabled(t, THREAD_DISABLED);
+	t->set_state(THREAD_BLOCKED);
+}
 
-	return current;
+/**
+ * Wake a Thread up that was previously waiting (see Scheduler::wait)
+ * @param t The Thread to wake up
+ */
+void Scheduler::wake(Thread *t)
+{
+	set_enabled(t, THREAD_DISABLED);
+	t->set_state(THREAD_READY);
+}
+
+/**
+ * Select a Thread. This implementation defaults to round-robin, if a
+ * thread is not already provided.
+ *
+ * @param t Thread to run, if chosen by an external entity (e.g.,
+ * ModelChecker). May be NULL to indicate no external choice.
+ * @return The next Thread to run
+ */
+Thread * Scheduler::next_thread(Thread *t)
+{
+	if ( t == NULL ) {
+		int old_curr_thread = curr_thread_index;
+		while(true) {
+			curr_thread_index = (curr_thread_index+1) % enabled_len;
+			if (enabled[curr_thread_index]) {
+				t = model->get_thread(int_to_id(curr_thread_index));
+				break;
+			}
+			if (curr_thread_index == old_curr_thread) {
+				print();
+				return NULL;
+			}
+		}
+	} else {
+		curr_thread_index = id_to_int(t->get_id());
+	}
+
+	current = t;
+	print();
+	return t;
 }
 
-Thread *Scheduler::get_current_thread(void)
+/**
+ * @return The currently-running Thread
+ */
+Thread * Scheduler::get_current_thread() const
 {
 	return current;
 }
+
+/**
+ * Print debugging information about the current state of the scheduler. Only
+ * prints something if debugging is enabled.
+ */
+void Scheduler::print() const
+{
+	if (current)
+		DEBUG("Current thread: %d\n", id_to_int(current->get_id()));
+	else
+		DEBUG("No current thread\n");
+}